Conventionally, a metallic material such as Nb-Ge (for example, Nb.sub.3 Ge) and the like is used as a superconducting material. This material has high ductility, malleability and bending property since it is a metal, and can be used for a coil in a superconducting magnet and also as an electrical accumulator coil.
However, the onset of the superconducting critical temperature (hereinafter referred to as Tc) of this metal is low, that is only 23.degree. K. or lower. Also, if industrial applications of the material are considered, it is extremely important that the Tc be 100.degree. K. or higher, and that the temperature where the electrical resistance becomes zero (hereinafter referred to as Tco) be 77.degree. K. or higher.
Recently, a copper oxide ceramic has been attracting considerable attention as such a superconducting material. However, the copper oxide ceramic material is deficient in ductility, malleability and bending property, and difficult to process after forming.
Accordingly, it is required to develop an application of the copper oxide ceramic material to a coil member for use in the magnet or power accumulator device.